The human body contains a wide variety of natural valves, such as, for example, heart valves, esophageal and stomach valves, intestinal valves, and valves within the lymphatic system. Natural valves can degenerate for a variety of reasons, such as disease, age, and the like. A malfunctioning valve fails to maintain the bodily fluid flow in a single direction with minimal pressure loss. An example of a malfunctioning valve is a heart valve that may be either stenotic, i.e., the leaflets of the valve are do not open fully, or regurgitant, i.e., the leaflets of the valve do not close properly. It is desirable to restore valve function to regain the proper functioning of the organ with which the valve is associated. For example, proper valve function in the heart ensures that blood flow is maintained in a single direction through a valve with minimal pressure loss, so that blood circulation and pressure can be maintained. Similarly, proper esophageal valve function ensures that acidic gastric secretions do not irritate or permanently damage the esophageal lining.
Several percutaneous prosthetic valve systems have been described. One example described in Andersen, et. al. (U.S. Pat. No. 5,411,552) comprises an expandable stent and a collapsible valve which is mounted onto the stent prior to deployment. The collapsible valve may be a biological valve or it may be made of synthetic material. The Anderson prosthetic valve is delivered and deployed using a balloon catheter which balloon is used to expand the valve-stent prosthesis to its final size. See also, U.S. Pat. No. 6,168,614 (Andersen, et al.) entitled “Valve Prosthesis for Implantation in the Body” and U.S. Pat. No. 5,840,081 (Andersen, et al.) entitled “System and Method for Implanting Cardiac Valves.”
Spenser, et. al. (U.S. Pat. No. 6,893,460) describe another prosthetic valve device comprising a valve structure made of biological or synthetic material and a supporting structure, such as a stent. The Spenser prosthetic valve is a crimpable leafed-valve assembly consisting of a conduit having an inlet and an outlet, made of pliant material arranged to present collapsible walls at the outlet. The valve assembly is affixed to the support stent prior to deployment. The complete valve device is deployed at a target location within the body duct using a deploying means, such as a balloon catheter or a similar device.
Accurate placement of current percutaneous valve devices relative to the existing native anatomy is often problematic, particularly in the case of aortic valve replacements. A prosthetic aortic valve that is placed too distally (relative to the heart, i.e., toward the aorta) can occlude or impede flow into the orifices of the coronary arteries. For example, depending on the position of the coronary ostia, either the skirt of the prosthetic valve or large native valve leaflets, when pressed down against the aorta wall, may physically or functionally obstruct the orifices and impede coronary arterial flow. See, e.g., Piazza, N., et al., “Anatomy of the Aortic Valvar Complex and Its Implications for Transcatheter Implantation of the Aortic Valve,” CIRCULATION CARDIOVASCULAR INTERVENTIONS, 1:74-81 (2008); Webb, J G, et al., “Percutaneous aortic valve implantation retrograde from the femoral artery,” CIRCULATION, 113:842-850 (2006). This obstruction may be either physical or it may be functional, i.e., the orifices of the coronary arteries are physically patent, but due to alterations in flow patterns produced by the prosthetic valve, flow into the coronary arteries is partially impeded. A prosthetic valve that is placed too proximally (i.e., toward the ventricular outflow tracts of the left ventricle) can interfere with the anterior leaflet of the Mitral valve, the atrioventricular node, or the bundle of His (conduction tissues). Approximately thirty percent of patients receiving prosthetic valves percutaneously require pacemakers, because the valve is placed with the ventricular end too close to or on top of the left bundle branch, putting pressure on the electrical conduction apparatus. See, e.g., Piazza, N., et al., “Early and persistent intraventricular conduction abnormalities and requirements for pacemaking following percutaneous replacement of the aortic valve,” JACC CARDIOVASCULAR INTERVENTIONS, 1:310-316 (2008); Piazza, N., et al., “Anatomy of the Aortic Valvar Complex and Its Implications for Transcatheter Implantation of the Aortic Valve,” CIRCULATION CARDIOVASCULAR INTERVENTIONS, 1:74-81 (2008).
Therefore, a need exists for improved placement and more simplified delivery of artificial valves and to increase the safety and accuracy of the percutaneous valve replacement procedure.
It is an object of the invention to provide a system and method of accurately placing a prosthetic valve device percutaneously in a lumen. Another object of the invention is to provide accurate placement of a prosthetic valve device that is minimally invasive.